The Astronomik UHC is THE filter for visual observing.

You will enjoy using your Astronomik UHC filter because you will see more stars and more details in deep-sky objects compared to filters from other manufacturers.

The Astronomik UHC (Ultra High Contrast) filter allows the transmission of nearly 100% of the radiation from both O-III and H-beta lines. Though the second window for the H-alpha line is not intended for visual observing, it is important when used with electronic devices. All annoying, scattered light from other wavelengths, including local artificial light pollution, is filtered out effectively. With this strong blocking of the sky background, an unexpected wealth of detail becomes visible in gas nebulae and planetary nebulae.

Main use

Astronomik UHC filters’ astounding high light transmission brings better views of deep-sky objects even to small telescopes! The high transmission of our optical glass filters means that enough light is available to allow successful visual observations with telescopes starting at 50mm aperture. Our Astronomik filters are optimized for use with telescope focal ratios from f/4 to f/15. Transmission losses and chromatic distortions that occur with other filters only appear with Astronomik filters when extremely bright aperture ratios of 1:2 or more come into play. Another major advantage of the Astronomik UHC filter is the high optical quality of the filter glass. When using Astronomik UHC filters, you will quickly notice the same needle-sharp stars you are familiar with from your astronomical instrument without any filter!

Suitability

• Visual observation (dark skies): Very good for telescopes of all apertures and high exit pupils
• Visual observation (urban skies): Very good for telescopes with a 100 mm aperture or larger
• Film photography: Reasonable, but requires very long exposure times
• CCD photography: Good when used with an additional IR-block filter
• DSLR photography (original): Good, with color balance shifted but contrast enhanced
• DSLR photography (astro modified): Very good, with near-perfect color balance
• DSLR photography (MC modified): Good when used with an additional IR-block filter
• Webcam / Video (Planets): Unsuitable
• Webcam / Video (Deep Sky): Good, especially if light pollution is a significant problem

Technical Data

• Typical 95% transmission at 486nm (H-beta)
• Typical 95% transmission at 496nm (O-III)
• Typical 95% transmission at 501nm (O-III)
• Typical 95% transmission at 656nm (H-alpha)
• Optimum position of transmission for telescopes with focal ratios from f/10 to f/3.5
• Entire blocking of annoying wavelengths
• Ideal all-around deep sky filter even for small telescopes
• Not sensitive to humidity or aging
• Scratch-resistant!
• Excellent carrier material – the optical performance of your telescope is not reduced by the filter in any way
• Parfocal with other Astronomik filters
• Glass thickness: 1mm
• Completely resistant to high humidity, scratches, and aging effects
• Diffraction limited – the filter will not reduce the optical performance of your telescope!
• Astronomik filters are delivered in a high-quality, long-lasting filter box